rain can add poluntants to the water depending on the wind's direction and whether it blows in from a heavily industrialized
city. Monitor your PH incase it starts to get hard. It can quite easily be buffered.

Some of my favorite stories about this came from Kentaro at Sakai hiroshima. Working hard all day and hitting the rack for sleep only to be awaken by a PH monitor in the tosai ponds. So back up and working to buffer the PH and at the end of the night with no sleep back to work for normal day's jobs. No rest for the weary. But understandable if you have a fortune in living creatures that have to be protected. ( and you thought being a breeder was the best career one could have )

Hi Marcrus, I have no idea about what part of the world you live. In some areas rain water is the cleanest water they can get. Tap water is designed to be fit for humans not fish, various chemicals are added to clean it, most of these are toxic in one way or another.
MOST RAIN IS ACIDIC , caused by oxygen passing through carbon dioxide, producing carbonic acid.
Dick quite wrightly talks about industry,but many types of natural areas can affect your koi ponds.
Buffering agents such as sea shells or limestone added at end of your filter will help.
Having seen Sakais' Tosai I expect that each is known by name ( even if there are 10 000 )

Hi Marcrus, I have no idea about what part of the world you live. In some areas rain water is the cleanest water they can get. Tap water is designed to be fit for humans not fish, various chemicals are added to clean it, most of these are toxic in one way or another.
MOST RAIN IS ACIDIC , caused by oxygen passing through carbon dioxide, producing carbonic acid.
Dick quite wrightly talks about industry,but many types of natural areas can affect your koi ponds.
Buffering agents such as sea shells or limestone added at end of your filter will help.
Having seen Sakais' Tosai I expect that each is known by name ( even if there are 10 000 )

We live in Manila, Philippines. I'm pretty sure that the rain is acidic. Do we also need to change the water by half and add more salt? Can we add the seashells or limestones inside the filter?

Sounds pretty much what we are facing here in Malaysia . daily rain. Sometimes overfills my pond with now abt daily BD flush of 2-3% , just from rain water. Do buffer your pond with Oyster or big corals , i do it at 5kg corals per ton water. Never had any pH issues since topping up my coral buffers years ago. Also do keep some soda bicarbs handy just in case , though very unlikely needed if coral buffers are kept clean. I had a pleasant surprise just yesterday , tested some rain water collected in test tubes, guess what pH 7 !! long ago i recall something like pH 4-5. The kois just loves it and the TDS is low as ever with my feeding and water changing regime.

Sounds pretty much what we are facing here in Malaysia . daily rain. Sometimes overfills my pond with now abt daily BD flush of 2-3% , just from rain water. Do buffer your pond with Oyster or big corals , i do it at 5kg corals per ton water. Never had any pH issues since topping up my coral buffers years ago. Also do keep some soda bicarbs handy just in case , though very unlikely needed if coral buffers are kept clean. I had a pleasant surprise just yesterday , tested some rain water collected in test tubes, guess what pH 7 !! long ago i recall something like pH 4-5. The kois just loves it and the TDS is low as ever with my feeding and water changing regime.

Sorry no help here , its in one of the thread. How much gram for increase in 0.1 pH reading . Others pls help chime in.

thanks
ts

There is no magic parts per million (ppm) or milligrams per liter for adding baking soda. You add enough to achieve the desired measured result. Typically you add enough to bring acidic water to a more desired value in the 7.0-7.5 range. Naturally you need a good calibrated pH meter or test kit.

Personally I don't add baking soda to maintain pH. Every spring I add 30 pounds of crushed coral to the trays in the bakki shower. The coral will dissolve as needed to neutralize acids in the water. throughout the year And the off gassing in the shower helps reduce dissolved CO2 (which in water is carbonic acid).

Corals/ Oysters shell still preferred , actually corals (unwashed) have a bad rap as harbouring bact that leads to hikui . Is it a myth or reality in your locale? Bicarbs wrecks havoc if you are running with TDS measures. But works great if you have a pH drop, just drop in till pH reaches at least 6.5-7.

Just saw my status on this thread , join date Dec 2004 , that's 10 year exactly. Been longer into kois , the more i know , the more i know not !